//给定一个排序链表，删除所有重复的元素，使得每个元素只出现一次。 
//
// 示例 1: 
//
// 输入: 1->1->2
//输出: 1->2
// 
//
// 示例 2: 
//
// 输入: 1->1->2->3->3
//输出: 1->2->3 
// Related Topics 链表


//leetcode submit region begin(Prohibit modification and deletion)

import java.util.ArrayList;
import java.util.List;


/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if (head == null) {
            return null;
        }
        ListNode last = head;
        ListNode cur = head.next;
        List<Integer> listmap = new ArrayList<Integer>();
        listmap.add(last.val);
        while (cur != null){
            if (listmap.contains(cur.val)){
                last.next = cur.next;
                cur = cur.next;
            }else {
                listmap.add(cur.val);
                last = last.next;
                cur = cur.next;
            }
        }
        return head;
    }
}
//leetcode submit region end(Prohibit modification and deletion)
